The present invention is directed to the field of paper processing, and more particularly to a technique for producing 3-D glasses from paperboard.
It has long been known that a three dimensional effect may be reconstructed from a two dimensional projection by providing two different perspectives of the projection along with some means for the viewer to discriminate between the two perspectives. With specific regard to 3-D motion pictures, for example, the film is prepared by simultaneously shooting the desired object from two lenses angularly separated to simulate binocular vision, the perspectives of the left and right lenses corresponding to the perspectives of the left and right eyes. The information received by the left and right lenses must remain distinct on the film so that the associated left and right eye information can later be separated by the viewer. A conventional technique for providing this separation is to provide blue and red filters for the left and right lenses of the camera. To view a film recorded in this manner, blue and red filters are placed over the viewer's left and right eyes, and the left and right eye information will be reconstructed for the viewer, thus simulating a three dimensional image. For this purpose, "3-D glasses" made from paperboard or cardboard and red and blue cellophane film, have become widely used. The glasses are relatively inexpensive to make and can either be reused or disgarded after use. The demand for such glasses has recently experienced a dramatic increase in view of the resurgence of 3-D movies at theaters, and the emergence of 3-D broadcasting over commercial television stations.
The prior art technique for producing 3-D glasses has been to process each set of glasses substantially individually. That is, the glasses have heretofore been individually produced in series from a long strip of paper, thus raising production costs. Also, buckling of the prior art eyeglass frames at the intersection of the front face of the glasses and the temples has been experienced during folding.